A new type of process promises opportunities for extruders to make lens arrays, now made primarily by injection or compression molding, for smartphone and other electronic displays, solar concentrators, optical diffusers, security products, etc.
Developed by Leap Technologies, Hillsboro, Wis., the proprietary process is described by its developer, David Roberts, as a coating technique that permits lens arrays to be produced by high-volume extrusion with no seams and distortions In conventional extrusion, Roberts explains, neck-in resulting from pulling the sheet from the chill roll causes loss of geometric integrity, or distortions.
“The real advancement for us was the ability to diamond-tool engrave very high precision optical lens arrays seamlessly around large embossing rolls” says Roberts. “This, coupled with an improved high-volume web reproduction process allows the arrays to be used for applications where they were previously only available through injection or compression molding. The result is reduced cost, increased production speeds, and larger array sizes.”
Leap Technologies is providing engraved chill rolls and processing expertise to processors looking to add lens arrays to their product mix. Lens arrays are diamond-tool engraved with submicron accuracy into embossing rolls, which impart the patterns to polyesters, polyolefins, and other materials, depending on the application. Web widths can be up to 1.5 meters, and film gauges from 100 to 500 microns. Lens arrays can cover the entire web, continuous stripes, or discrete zones.